Question

Which of the following substances turn blue litmus paper to red?

• A. Lemon juice
• B. Carbonated soft drink
• C. Curd
• D. All of the above

Answer 1

Answer: (D)

All of the above

(A) Lemon juice is citric acid, so it turns blue litmus paper red.

(B) Carbonate soft drink contains carbon dioxide dissolved in water. Carbon dioxide forms carbonic acid with water which turns blue litmus paper red.

(C) Curd contains lactic acid and hence turns blue litmus paper to red.